Efficient

(ef-fish'ent), a. [Fr. efficient, Lat. efficiens, p. pr. of efficere. See EFFECT, v. t.] Causing effects; producing results; actively operative; not inactive, slack, or incapable; characterized by energetic and useful activity. “The efficient cause is the working cause.” Wilson.

Synonyms—Effective; effectual; competent; able; capable.

n. The agent or cause which produces, or causes to exist; a prime mover.

God . . . moveth mere natural agents as an efficient only. Hooker.